Indeed, the mileage claims made by automakers play a key role in a multibillion-dollar industry that deserves close government scrutiny. But what happens when the regulators fall down on the job?

The federal Environmental Protection Agency has failed consumers with its abysmal handling of a controversy involving the fuel efficiency of some recent Hyundai and Kia vehicles.

The EPA won’t tell the public specifics about the problems involving auto mileage estimates from the two automakers.

The EPA also won’t comment when asked about how well the annual fuel economy standard tests are overseen by the government these days.

Finally, it’s extremely disappointing that environmental groups had to pressure the EPA for many months to even do its job and check into complaints about lower-than-expected mileage for certain vehicles.

The entire episode amounts to a shocking dereliction of duty by the EPA. It also, unfortunately, gives critics in Congress ammunition to attack the agency, which has important roles to play when it comes to cleaning up the nation’s air and water.

For decades, the America public has come to believe that the EPA essentially endorses whatever mileage statements are made by General Motors, Ford, Chrysler, Toyota, Honda and other carmakers.

But the controversy involving Hyundai and Kia tarnishes those two companies and the EPA. Plus, other major auto manufacturers such as GM are left to wonder whether the public will now distrust their estimates, too.

So were the recent errors honest mistakes? No one knows because the carmakers have not disclosed exactly what might have gone wrong.

Another problem: The EPA reportedly does not hire an outside expert to randomly check vehicles on the accuracy of their stated mileage claims using the same test that apparently brought to light the latest problems. Why did the agency stop such monitoring? Will it restart the program?

Cue up the once-again mum EPA officials who, as The Star noted, also refused to provide documents about the entire matter.

So much for being a public watchdog. In this case, the EPA seems more like an apologist for bad behavior by parts of the auto industry.

Editorial by the Kansas City Star